XML
http://www.xml.com
XML Overview
http://www.zdnet.com/devhead/stories/articles/0,4413,2322718,00.html
http://www.softwareag.com/xml/dt/Techn_Links/glossar.htm
http://wdvl.internet.com/Authoring/Languages/XML/Tutorials/Intro/history.html
http://www.impressions.com/resources_pgs/SGML_pgs/SGMLintr.html
http://www.zdnet.com/devhead/stories/articles/0,4413,2322551,00.html
http://www.washington.edu/computing/training/540/tree.html
http://www.devguru.com/Features/tutorials/XML/beginning_xml.html
Style
http://www.brics.dk/~amoeller/XML/xslt.html
http://www.w3.org/Style/CSS-vs-XSL
http://www.xml.com/pub/r/320
http://www.dpawson.co.uk/
http://www.nwalsh.com/docs/tutorials/xsl/index.html
http://www.finetuning.com/xpathfaqcontent.html
http://www.renderx.com/tutorial.html
http://www.nwalsh.com/docs/tutorials/xsl/xsl/titlefoil.html
Linking
http://www.oasis-open.org/cover/xlinkMaler980402.html
http://www.oasis-open.org/cover/xll.html
http://www.sun.com/software/xml/developers/xlink/
http://www.wdvl.com/Authoring/Languages/XLink/
http://www.zvon.org/xxl/xlink/OutputExamples/xlinksimple_intro.html
Validation
http://www.xml.com/pub/a/2000/11/29/schemas/part1.html
http://www.xml101.com/dtd/dtd_intro.asp
http://service2.boulder.ibm.com/devtools/news0300/artpage15.htm
APIs
http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/introduction.html
http://www.megginson.com/SAX/event.html
http://xml.apache.org/xalan-j/apidocs/javax/xml/transform/trax.html
File Formats
OpenOffice XML